Nickel complex pigments of bis-azomethines

ABSTRACT

Pigments that can be used to color plastics, paints, and printing inks have the structural formula ##STR1## wherein each R 1 , each R 3 , and R 7  represent hydrogen, halogen, nitro, or lower alkyl and each R 2 , each R 4 , each R 5 , and R 6  represent hydrogen or halogen.

This application is a division of application Ser. No. 542,019, filed10/14/83, now U.S. Pat. No. 4,508,899.

This invention relates to metal complex pigments. More particularly, itrelates to nickel complex pigments of bis-azomethines and to a processfor making these pigments.

In accordance with this invention, it has been found that 1:1 nickelcomplex pigments of bis-azomethines can be used to color plastics,lacquers, and printing inks in yellow to orange shades and haveoutstanding fastness properties.

The novel pigments of this invention are nickel complexes of1,2-phenylene-bis-(2-azomethinyl-3-hydroxy-8-oxoquinazolo-[3,2-a]-quinolinesthat have the structural formula ##STR2## wherein each R¹, each R³, andR⁷ may represent hydrogen; halogen, that is, chlorine or bromine; nitro;or lower alkyl, that is, methyl, ethyl, propyl, or butyl; and each R²,each R⁴, each R⁵, and R⁶ may represent hydrogen or halogen.

While all of the nickel complexes are orange or yellow in color, theshade of the pigment is dependent upon the number of substituents, thenature of the substituents and the positions of the substituents on therings of the complex.

In general, halogen- or alkyl-substituted pigments are redder in shadethan the unsubstituted complex. The chloro-substituted products areusually stronger and cleaner pigments than the correspondingmethyl-substituted products. As their chlorine content increases, thepigments become redder in shade. The bromine-substituted complexes tendto be redder in shade than the corresponding chloro-substitutedcomplexes. When a single chlorine atom is introduced into the diaminebridge of the tetrabromo-complex, its shade becomes redder; when twochlorine atoms are introduced into the diamine bridge, a maroon pigmentis obtained. Those complexes in which R³ represents nitro are generallybrowner in tone than those in which the substituent in this position ischloro. When R⁶ represents nitro, the complex is considerably redder intone than the unsubstituted complex (R⁶ equals H).

The nickel complex pigments of this invention may be prepared by amulti-step process in which anN-(2-carboxyphenyl)-2-methyl-4-quinazolone is reacted withN-methylpyrrolidone and acetic anhydride to form a3-hydroxy-8-oxoquinazolo[3,2-a]-quinoline, which is then reacted withethyl N-phenylformimidate to form a phenyl azomethine. The phenylazomethine is reacted with a diaminobenzene and a water-soluble nickelsalt in an inert solvent to form the nickel complex.

The formation of the phenyl azomethine and the nickel complex are shownin the following equations: ##STR3##

The N-(2-carboxyphenyl)-2-methyl-4-quinazolones that are used in thefirst step of this process are prepared from anthranilic acid or asubstituted anthranilic acid by a process that is well known in the art.Among the substituted anthranilic acids that can be used are5-chloroanthranilic acid, 6-chloroanthranilic acid,4,6-dichloroanthranilic acid, 5-bromoanthranilic acid,5-methylanthranilic acid, and the like, and mixtures thereof.

The N-(2-carboxyphenyl)-2-methyl-4-quinazolone is then heated withacetic anhydride and N-methylpyrrolidone or a solvent such asN,N-dimethylacetamide or N,N-dimethylformamide at the reflux temperatureof the mixture to form a 3-hydroxy-8-oxoquinazolo-[3,2-a]-quinoline,which is recovered from the reaction mixture and air-dried.

This compound is then added to a reaction mixture obtained by heatinganiline with triethylorthoformate and an acid catalyst that may bep-toluenesulfonic acid in N,N-dimethylacetamide at its refluxtemperature until all of the byproduct ethanol has distilled off. Theresulting mixture is heated at its reflux temperature to form a phenylazomethine.

Simultaneous addition of 1,2-diaminobenzene or substituted1,2-diaminobenzene, such as 1,2-diamino-4-bromobenzene,1,2,-diamino-4-nitrobenzene, or 1,2-diamino-4,5-dichlorobenzene, awater-soluble nickel salt, and an inert solvent to the refluxing mixtureresults in the immediate precipitation of a colored product. Thisproduct is collected; washed with a hot solvent, such asdimethylformamide or dimethylacetamide, and then successively with waterand acetone; and dried. The 1:1 nickel complexes that are obtained maybe conditioned, for example, by ball milling with acetone, and then usedto color polyethylene, polyvinyl chloride, and other thermoplasticresins; paints; and printing inks. These colored products exhibit verygood light fastness, thermal stability, and resistance to migration.

The invention is further illustrated by the following examples:

EXAMPLE 1 (A) Preparation of 3-hydroxy-8-oxoquinazolo-[3,2-a]-quinoline

To a solution of 50 ml. (0.45 mole) of acetic anhydride and 60 ml. ofN-methylpyrrolidone at 120°-130° C. was added with stirring 28 grams(0.1 mole) of finely-powdered N-(2-carboxyphenyl)-2-methyl-4quinazolone,which had been prepared from anthranilic acid and acetic anhydride by aconventional process. The resulting solution was heated at its refluxtemperature for 5 hours. After the addition of 10 ml. of water, thereaction mixture was heated at its reflux temperature for 1 hour andthen cooled and filtered. The filter residue was washed well withacetone and air-dried. There was obtained 18.4 grams (70.2% of theory)of a beige solid which melted at 301° C. The structure of the productwas confirmed by analysis.

(B) Preparation of the nickel (2) Complex of1,2-phenylene-bis-(2-azomethinyl-3-hydroxy-8-oxoquinazolo-[3,2-a]-quinoline)

To a stirred solution of 14.8 ml. (0.089 mole) of triethylorthoformateand 0.2 gram of p-toluenesulfonic acid in 100 ml ofN,N-dimethylacetamide which had been heated to 100°-120° C. was added8.1 ml. (0.089 mole) of aniline over a period of 10 minutes. After thebyproduct ethanol had been distilled off, the solution was heated at itsreflux temperature for 1 hour. Then 15.5 grams (0.059 mole) of theproduct of part (A) was added to the solution in 10 minutes, and theresulting solution was heated at its reflux temperature for 1 hour.

Simultaneous addition of 6.5 grams (0.06 mole) of 1,2-diaminobenzene,8.6 grams (0.03 mole) of nickel nitrate.6H₂ O, and 4.9 grams (0.06 mole)of sodium acetate to the refluxing solution resulted in the immediateprecipitation of a red-yellow solid. The resulting suspension was heatedat its reflux temperature for 1 hour and then filtered hot. The filterresidue was washed thoroughly with dimethylacetamide and thensuccessively with water and acetone, and dried. There was obtained 13.3grams (58% of theory) of the nickel (2) complex, which was areddish-yellow solid that had a molecular weight of 708.7 and that wasfound by microanalysis to contain 67.83% C, 3.23% H, 11.84% N, and 8.08%Ni (calculated: 67.73% C, 3.10% H, 11.85% N, and 8.28% Ni).

(C) To 100 grams of granular polyethylene was added 0.2 gram of thepigment of part (B). The mixture was injection molded at 280°-300° C. toform pigmented chips. The red-shade tan chips exhibited very goodfastness to light and migration.

EXAMPLE 2 Preparation of the nickel (2) complex of1,2-phenylene-bis-(2-azomethinyl-3-hydroxy-6,11-dichloro-8-oxoquinazolo-[3,2-a]-quinoline

To a stirred solution of 34.9 ml. (0.21 mole) of triethylorthoformateand 0.5 gram of p-toluenesulfonic acid in 60 ml. of 1,2-dichlorobenzenewhich has been heated to 100°-120° C. was added with stirring 19.1 ml.(0.21 mole) of aniline over a period of 10 minutes. After the byproductethanol had been distilled off, the solution was heated at its refluxtemperature for 1 hour. Then 45.2 grams (0.137 mole) of finely-powdered3-hydroxy-6,11-dichloro-8-oxoquinazolo-[3,2-a]-quinoline was added tothe solution over a period of 15 minutes; the resulting mixture washeated at its reflux temperature for 2 hours and then cooled. Themixture was filtered, and the collected solid product was washedthoroughly, first with toluene and then with ligroine (60°-90° C.); andair-dried. There was obtained 47 grams (79% of theory) of a brightyellow phenyl azomethine that melted at 270°-273° C. and had thestructural formula ##STR4##

When a slurry of 6.6 grams (0.06 mole) of 1,2-diaminobenzene and 15grams (0.06 mole) of nickel acetate.4H₂ O in 100 ml. ofdimethylformamide was added to an efficiently agitated mixture of 47grams (0.11 mole) of the phenyl azomethine in 1300 ml. ofdimethylformamide at its reflux temperature, an orange-red precipitateformed immediately. After 2 hours at its reflux temperature, thereaction mixture was filtered hot. The filter residue was washedthoroughly with hot dimethylformamide and then with water and acetone;and then dried. There was obtained 45.8 grams (92% of theory) of theorange nickel (2) complex of1,2-phenylene-bis-(2-azomethinyl-3-hydroxy-6,11-dichloro-8-oxoquinazolo-[3,2-a]-quinoline)that had a molecular weight of 846.7 and that was found by microanalysisto contain 56.56% C, 2.48% H, 16.56% Cl, 9.87% N, and 7.10% Ni(calculated: 56.69% C, 2.13% H, 16.77% Cl, 9.92% N, and 6.93% Ni).

The product was dispersed in thermoplastic acrylic lacquer paint by ballmilling. A portion of the paint was extended with sufficient titaniumdioxide to give a final toner to white ratio of 5 to 95, and the twopaints were sprayed onto primer-coated aluminum panels. In each case, anorange finish of very good fastness to over-stripe bleeding, light, andatmospheric influences was obtained.

EXAMPLES 3-23

Using the procedure of Example 1 and the appropriate3-hydroxy-8-oxoquinazolo-[3,2-a]-quinolines, ethyl N-phenylformimidateand diaminobenzenes, a series of nickel complexes was prepared. Thestructures of these pigments and their colors are shown in the followingtable: ##STR5##

                  TABLE                                                           ______________________________________                                        Example                                                                              Substitutents                                                          No.    R.sup.1                                                                              R.sup.2                                                                             R.sup.3                                                                            R.sup.4                                                                           R.sup.5                                                                           R.sup.6                                                                           R.sup.7                                                                            Color                               ______________________________________                                         3     H      Cl    H    Cl  H   H   H    orange                               4     Cl     H     H    Cl  H   H   H    orange                               5     Cl     H     Cl   H   H   H   H    orange                               6     H      Cl    Cl   H   H   H   H    orange                               7     H      Cl    H    H   H   H   H    red-yellow                           8     Cl     H     H    H   H   H   H    yellow-orange                        9     H      H     Cl   H   H   H   H    yellow-orange                       10     H      Cl    Cl   H   Cl  H   H    red-orange                          11     H      Cl    Br   H   Br  H   H    red-yellow                          12     CH.sub.3                                                                             H     H    H   H   H   H    yellow-orange                       13     H      H     CH.sub.3                                                                           H   H   H   H    yellow-orange                       14     CH.sub.3                                                                             H     CH.sub.3                                                                           H   H   H   H    yellow-orange                       15     H      Cl    H    Cl  H   Cl  Cl   red-orange                          16     H      H     H    H   H   Cl  H    yellow-orange                       17     H      H     NO.sub.2                                                                           H   H   H   H    brownish-orange                     18     H      H     H    H   H   H   NO.sub.2                                                                           red-orange                          19     Br     H     Br   H   H   H   H    red-orange                          20     Br     H     Br   H   H   Cl  H    red-orange                          21     Br     H     Br   H   H   Cl  Cl   maroon                              22     H      H     Br   H   H   H   H    orange                              23     H      H     Br   H   H   Cl  H    red-orange                          ______________________________________                                    

What is claimed is:
 1. A process for the production of nickel complexeshaving the structural formula ##STR6## wherein each R¹, each R³, and R⁷represent hydrogen, halogen, nitro, or lower alkyl and each R², each R⁴,each R⁵, and R⁶ represent hydrogen or halogen, that comprises the stepsof(a) heating an N-(2-carboxyphenyl)-2-methyl-4-quinazolone withN-methylpyrrolidone and acetic anhydride to form a3-hydroxy-8-oxoquinazolo-[3,2-a]-quinoline having the structural formula##STR7## (b) heating the product of step (a) with ethylN-phenylformimidate having the structural formula ##STR8## in thepresence of an acid catalyst to form a phenyl azomethine having thestructural formula ##STR9## and (c) reacting said phenyl azomethine witha diaminobenzene having the structural formula ##STR10## and awater-s9oluble nickel (II) salt in an inert solvent to form the nickelcomplex.
 2. The process of claim 1 wherein theN-(2-carboxyphenyl)-2-methyl-4-quinazolone used in step (a) is theproduct of the reaction of an anthranilic acid and acetic anhydride. 3.The process of claim 1 wherein the water-soluble nickel (II) salt usedin step (c) is nickel (II) nitrate.6H₂ O.
 4. The process of claim 1wherein the water-soluble nickel (II) salt used in step (c) is nickel(II) acetate.4H₂ O.
 5. The process of claim 1 wherein the product formedin step (a) is 3-hydroxy-6,11-dichloro-8-oxoquinazolo-[3,2-a]-quinoline.6. The process of claim 1 wherein in step (c) the product of step (b) isheated with 1,2-diaminobenzene in the presence of a water soluble nickel(II) salt in an inert solvent.